14
Operation and Maintenance Manual
QC Series Centrifugal Pump
QC-M02
Please remember that the PTFE gaskets (
80P
) and (
80R
) are not interchangeable.
The seal seat (
80N
) is made of a very strong material and therefore is very fragile. It is important to
protect the faces of the stationary seal just as with the backplate, against bumps and scratches.
Screw the gland ring into the backplate, using the screws (
17K
) and lock washers (
17M
). Screw
in the backplate pins (
11F
) to the backplate if applicable. See
Figure E.
Just tighten the screws
until the washers are flattened, any tighter and you may crack the stationary seal.
Assemble the “D” seal components onto the stub shaft (as explained in the
section regarding the “D” seal) taking care that the o-ring remains inside of
the carbon. Once both preassemblies are complete, that of the “DG” seal
onto the backplate and that of the “D” seal, take the backplate and push
on the “D” seal sliding it onto the stub shaft.
Be very careful not to hit the “DG” seal with the end of the stub shaft. Now,
set the backplate onto the adapter. Although space appears to be limited,
the spring can be compressed until the drive collar completely touches the
o-ring.
Once the backplate is set onto the adapter, push the drive collar against the backplate to
compress the spring. Tighten the set screws to set the seal when the spring no further can
move.
The efficiency of the “D” and “DG” seals relies upon the position of the o-ring inside the carbon
as well as the full compression of the spring.
Figure F.
“DG” type seal is used to handle fluids that
crystallize when allowed to settle for a time.
When pumping abrasive or corrosive fluids,
combine the “DG” seal with EPDM gaskets.
EPDM gaskets are resistant to certain harsh
chemicals. For more information, please
contact either the plant or your distributor.
WATER COOLED BALANCED DOUBLE SEAL
TYPE “E”.
This mechanical seal is very different from
the previous three, although it shares some common
components. It consists of two balanced, rotating
parts, placed into a stuffing box, which is normally
flooded to cool the seal.
The “E” seal consists of the following parts. Find and
keep them at hand to make the assembly process
easier: stuffing box “E” (
83C
), o-ring (
83E
), machine screw (
83D
), follower (
17
), o-ring (
17B
),
machine screw (
17A
), and lock washers (
17C
) for the follower, “E” seal backplate (
11B
), backplate
pins (
11F
), spring (
80H
), drive collar “E” (
80J
), set screw drive collar (
80M
), two carbon seals
(
80
), two o-rings (
80B
) and two cups (
80G
). It is recommended to have a caliper on hand to
assemble this seal precisely.
ASSEMBL
Y